1. Field of the Invention
The present invention relates to a method of fabricating a longitudinal rail for supplying a mobile with electrical power.
2. Description of the Prior Art
Said rail includes two electrically conductive longitudinal components which are fastened together and have respective substantially constant cross sections and a common median longitudinal plane of symmetry, namely a mounting body adapted to be mounted on a support and a wear plate which is worn by said mobile,
said mounting body including, in mutually opposed positions in a transverse direction in said plane, a rigid longitudinal base for mounting it on said support and a longitudinal head for receiving said wear plate, which head is delimited in the direction away from said base in said transverse direction by an electrically conductive face straddling said plane and having a rebate in the direction away from said plane on respective opposite sides of said electrically conductive face,
said plate including a flat central strip for transmitting electrical power to said mobile, straddling said plane, having opposite said base in said transverse direction a contact face for said mobile and facing toward said base in said transverse direction an electrically conductive face bearing flat on said electrically conductive face of said body and two lateral rims on respective opposite sides of said plane and forming a projection toward said base in said transverse direction relative to said central strip, each of said rims having, facing toward said plane, an attachment face for attaching it to said body, which attachment face converges with said plane in the direction away from said central strip in said transverse direction to define a hook shape interengaged with a respective rebate so that said wear plate is fastened to said head of said mounting body by a mutual nesting effect.
Non-limiting examples of mobiles that can be supplied with electrical power include certain rail vehicles, such as metros, and some lifting or materials handling plant, such as travelling overhead cranes, moving along a particular trajectory along which are placed one or more lengths of a rail of the type indicated in the preamble, on the wear plate of which presses an electrical pick-up member such as a shoe carried by the mobile.
In this regard, a rail of the type to which the present invention relates can equally well be rectilinear or curved, and in the latter case, as will be obvious to a person skilled in the art, a median fiber of the rail is taken as the longitudinal reference and a surface defined by respective axes of symmetry of different sections of the rail perpendicular to its median fiber are taken as the median plane of symmetry.
Various designs of electrical power supply rails consisting of the association of a mounting body and a wear plate fastened together are well known in the art and widely used.
The mounting body is generally used to mount the rail on supports such as insulators and can itself be used to mount electrically insulative caps to protect against accidental contact with the power supply rail. Its cross section is generally much greater than that of the other component, and is determined on the one hand by the stiffness to be imparted to the rail and on the other hand by the current that is to flow in it. To reduce its weight, for a given cross section, the mounting body is generally made of aluminum or aluminum alloy.
The wear plate, which is adapted to cooperate with the electrical pick-up member carried by the mobile, is therefore made from stainless steel, for example, which is more resistant to wear than aluminum or aluminum alloy, although more dense, or of copper or brass. Its cross section is limited to that necessary to insure a particular minimum time of operation, at the end of which it is completely worn down, and its shape can vary according to the manner in which it is fastened to the mounting body.
One fastening method relying on clipping of the rims of the wear plate into rebates on the head of the mounting body, as indicated in the preamble, is used by the company BRECKNELL WILLIS, which employs an aluminum mounting body which is rigid, especially in the area of its head, and two stainless steel members, each of which corresponds to one half of the wear plate, i.e. to one of the parts thereof defined by the median plane of longitudinal symmetry. The electrically conductive faces of the mounting body, the central strip of the wear plate, and the contact face for the mobile are plane and perpendicular to the median longitudinal plane of symmetry. To assemble the wear plate to the mounting body, the two parts of the wear plate, which are initially independent of each other, are heated to a temperature higher than that of the mounting body and applied to the head thereof so that the corresponding respective half of the central strip is applied to a respective half of the electrically conductive face of the head and their rims are pressed against the corresponding respective rebates; when the two parts are perfectly face-to-face in this way, in the median longitudinal plane of symmetry, they are welded together and the assembly is then allowed to cool, whereby, because of the different coefficients of thermal expansion of stainless steel and aluminum, the wear plate grips the head of the mounting body and is fastened to it by this gripping effect alone.
However, the pressure applied by the stainless steel wear plate to the aluminum mounting body is afterwards closely dependent on temperature, and in the event of extremely low temperatures the pressure can be insufficient to retain the wear plate against movement in longitudinal translation on the mounting body and to insure an adequate quality of electrical conduction between the two components of the rail.
French patent FR-A-2 227 148 discloses a variant of the method indicated in the preamble including a succession of steps, the first of which consists of separately prefabricating:
said mounting body, conforming it so that said head is divided in said plane into two halves joined together by said base and delimiting between them a longitudinal slot open in the direction away from said base in said transverse direction, each of said two halves having opposite said base in said transverse direction a free end including a respective half of said electrically conductive face of said body and a respective rebate and being adapted to flex elastically relative to said base, in particular toward each other from a rest configuration in which said mounting body is prefabricated and as far as a maximum elastic flexing configuration, said two halves of said electrically conductive face of said body having an orientation relative to said plane such that they diverge from said base in said transverse direction toward said plane in said rest configuration, and
said wear plate, conforming it so that its rims define between them, perpendicularly to said plane, in an area of closest approach thereto in the direction away from the central strip in said transverse direction, a width less than the maximum width of said head perpendicularly to said plane between said halves of said electrically conductive face of said body and said rebates, in said rest configuration,
The wear plate and the mounting body are therefore made in one piece, and the next step consists of forcibly nesting the wear plate over the head of the mounting body, by virtue of elastic flexing of the wear plate such that its rims move apart and elastic flexing of the two halves of the head such that they move toward each other until they abut against each other, which defines a maximum elastic flexing configuration that the two halves of the head retain at the end of fabrication of the rail and in which the slot is closed.
A final step consists of permanently fastening the wear plate to the mounting body by spiking, riveting or welding the rims of the wear plate to the head of the mounting body.
The above document teaches respectively concave and convex V-shaped cross sections for the electrically conductive faces of the wear plate and the mounting body, so that any tendency for the mounting body to resume its rest configuration by virtue of its elasticity is reflected in a tendency of the wear plate to press its electrically conductive face firmly flat against the electrically conductive face of the mounting body.
However, obtaining the above effect inevitably gives rise to major problems in that the wear plate is nested over the head of the mounting body with elastic prestressing such that it overcomes the elastic tendency of the two halves of the head to move apart from the relative position that they occupy at the end of fabrication of the rail, i.e. a relative position in which they abut one against the other and in which the slot that they define is closed, and the fact that the rims of the wear plate are firmly spiked, riveted or welded to the head of the mounting body after nesting, would seem more likely to oppose it.
Accordingly, given the coefficients of thermal expansion of the materials of the wear plate and the mounting body, namely stainless steel and aluminum or aluminum alloy, respectively, the electrically conductive face of the wear plate tends rather to move away from that of the mounting body if the temperature falls below the fabrication temperature, in which case the mutual contact pressure can be significantly reduced.
The spikes, rivets or welds joining the wear plate to the mounting body then undoubtedly oppose relative longitudinal sliding, but the quality of the electrical conduction between the wear plate and the mounting body is not insured.
What is more, the necessity for the wear plate to flex elastically in order for it to nest over the head of the mounting body and then to hold it elastically prestressed thereon imposes the choice for the wear plate of a semi-hard spring stainless steel, which is particularly fragile and costly, and necessarily limits the choice of geometrical characteristics that can be imparted to the wear plate; in particular, it must be relatively thin, which limits its service life.
What is more, the convex cross section that the face of the wear plate in contact with the electrical pick-up member carried by the mobile necessarily has in this case means that the pick-up member must have a concave shape, with a cross section complementary to the convex cross section, which complicates the manufacture of the pick-up member and rules out any transverse offset between it and the rail, i.e. mounting the pick-up member on the mobile, whose effective trajectory is rarely rigorously parallel to the rail, is made more complicated.
The object of the present invention is to remedy the above drawbacks of the prior art and, to this end, the present invention proposes a method of fabricating a longitudinal rail for supplying a mobile with electrical power, said rail including two electrically conductive longitudinal components which are fastened together and have respective substantially constant cross sections and a common median longitudinal plane of symmetry, namely a mounting body adapted to be mounted on a support and a wear plate which is worn by said mobile,
said mounting body including, in mutually opposed positions in a transverse direction in said plane, a rigid longitudinal base for mounting it on said support and a longitudinal head for receiving said wear plate, which head is delimited in the direction away from said base in said transverse direction by an electrically conductive face straddling said plane and having a rebate in the direction away from said plane on respective opposite sides of said electrically conductive face,
said plate including a flat central strip for transmitting electrical power to said mobile, straddling said plane, having opposite said base in said transverse direction a contact face for said mobile and facing toward said base in said transverse direction an electrically conductive face bearing flat on said electrically conductive face of said body and two lateral rims on respective opposite sides of said plane and forming a projection toward said base in said transverse direction relative to said central strip, each of said rims having, facing toward said plane, an attachment face for attaching it to said body, which attachment face converges with said plane in the direction away from said central strip in said transverse direction to define a hook shape interengaged with a respective rebate so that said wear plate is fastened to said head of said mounting body by a mutual nesting effect,
said method including a succession of steps, the first of which consists of:
a) prefabricating separately:
said mounting body, conforming it so that said head is divided in said plane into two halves joined together by said base and delimiting between them a longitudinal slot open in the direction away from said base in said transverse direction, each of said two halves having opposite said base in said transverse direction a free end including a respective half of said electrically conductive face of said body and a respective rebate and being adapted to flex elastically relative to said base, in particular toward each other from a rest configuration in which said mounting body is prefabricated and as far as a maximum elastic flexing configuration, said two halves of said electrically conductive face of said body having an orientation relative to said plane such that they diverge from said base in said transverse direction toward said plane in said rest configuration, and
said wear plate, conforming it so that its rims define between them, perpendicularly to said plane, in an area of closest approach thereto in the direction away from the central strip in said transverse direction, a width less than the maximum width of said head perpendicularly to said plane between said halves of said electrically conductive face of said body and said rebates, in said rest configuration,
in which method, in step a), there are also prefabricated:
said mounting body, conforming it so that said two halves of said electrically conductive face of said body have an orientation relative to said plane such that they converge toward said base in the direction toward said plane in said maximum elastic flexing configuration and in a particular intermediate elastic flexing configuration, in which said slot is still open in the direction away from the base in said transverse direction, they are mutually coplanar and perpendicular to said plane and then constitute said electrically conductive face of said body, which is plane and perpendicular to said plane, and
said wear plate, permanently conforming it so that said contact face for the mobile and said electrically conductive face of said central strip are plane and perpendicular to said plane and its rims define between them, perpendicularly to said plane, in an area of closest approach thereto in the direction away from said central strip in said transverse direction, a width less than the maximum width of said head, perpendicularly to said plane, between said halves of said electrically conductive face of said body and said rebates, not only in said rest configuration but also in said particular intermediate configuration, but at least equal to, and in particular greater than, the maximum width of said head perpendicular to said plane between said halves of said electrically conductive face of said body and said rebates, in said maximum elastic flexing configuration, and at least equal to, and in particular greater than, the minimum width of said head, perpendicularly to said plane, at the level of said rebates in said particular intermediate configuration, and so that said attachment faces define with said electrically conductive face of said wear plate a shape complementary to the shape that said rebates define with said electrically conductive face of said body in said particular intermediate configuration,
and which method includes, after step a), the following succession of steps:
b) applying to said two halves of said head opposite thrusts to move them toward each other, perpendicular to said plane, from said rest configuration to said maximum elastic flexing configuration,
c) maintaining said thrusts to retain said two halves of said head in said maximum elastic flexing configuration, nesting said wear plate over said head to place said electrically conductive face of said wear plate in bearing engagement with said halves of said electrically conductive face of said body and to place said rims on respective opposite sides of said head, facing said rebates, and
d) releasing said thrusts while holding said electrically conductive face of said wear plate in bearing engagement with said halves of said electrically conductive face of said body so that said two halves of said head flex elastically toward each other, perpendicularly to said plane, and said rebates abut in this direction against said attachment faces of said rims of said wear plate, which hold said two halves of said head prestressed in elastic flexing in said particular configuration in which said two halves of said electrically conductive face of said body are also mutually coplanar and said electrically conductive face of said wear plate is therefore pressed flat against it.
It will be obvious to the person skilled in the art that, in this case, the pressure applied by the two halves of the head of the mounting body, which is advantageously prefabricated in one piece during step a) from a material chosen from the group comprising aluminum and aluminum alloys, on the wear plate, which is also advantageously made in one piece during step a) from a material chosen from the group comprising stainless steel, copper and copper alloys, depends almost exclusively on the elastic properties of the material of the mounting body and the flexing applied to the halves of the head in said intermediate flexing configuration, in comparison with the rest configuration. That pressure is therefore practically constant and independent of temperature, or can in any event be high enough for any variations that may result from differential thermal expansion to remain sufficiently low, in comparison, for it to be sure that the pressure remains sufficiently high in all circumstances to prevent movement in translation of the wear plate relative to the mounting body and to preserve good electrical conduction between the mounting body and the wear plate.
What is more, compared to the prior art technique previously mentioned, it is faster, less costly and more reliable to produce a rail by the method according to the invention.
In particular, compared to the BRECKNELL WILLIS technique, it is not necessary to weld several initially separate parts of the wear plate, which means that the equipment necessary for such welding can be dispensed with, as can the reworking steps necessary to obtaining an appropriate flatness and surface state of the face of the wear plate in contact with the mobile. What is more, although machining the weld, in practice milling it, generally causes a median longitudinal depression in the contact face, accelerating wear of the electrical pick-up member carried by the mobile, when the BRECKNELL WILLIS technique is used, the possibility of making the wear plate in one piece when the method according to the invention is used means that its face in contact with the mobile can be flat without discontinuities in the transverse direction, reducing wear of the electrical pick-up member carried by the mobile.
Compared to the technique described in FR-A-2 227 148, it is not necessary to rely on the elasticity of the wear plate, and to the contrary its cross section can be considered to be non-deformable in comparison with the mounting body, which gives a greater choice as to the steel used, which can be less fragile and less costly than spring steel, and a greater choice as to the thickness of the plate, which can therefore be sufficiently thick to have a satisfactory service life.
What is more, the wear plate is retained on the head entirely by the elasticity of the mounting body and the respective conformations of its head and the wear plate, which makes it possible to dispense with any other form of fastening them together by spiking, riveting or welding, together with the reworking operations and equipment needed for this.
What is more, compared to the technique described in FR-A-2 227 148, the method of the invention provides the benefit of a flat face of the wear plate in contact with the mobile, which simplifies the manufacture and the mounting of the electrical pick-up member carried by the mobile, even if longitudinal movement of the mobile is accompanied by some transverse movement relative to the rail.
As is known in the art, the electrical conduction between the head of the mounting body and the wear plate can naturally be improved and all risk of penetration of an electrolyte between them avoided by applying a contact grease to at least one of said electrically conductive faces, and preferably to the rebates and/or the attachment faces, prior to step c). Such application is preferably immediately preceded or accompanied by brushing them clean; in particular, when the mounting body is made of aluminum or aluminum alloy, brushing the electrically conductive face of the body, and preferably also of the rebates, eliminates from them the alumina that would compromise electrical conduction with the wear plate, which alumina is prevented from forming again by applying a neutral contact grease immediately afterwards.
The fabrication method in accordance with the invention can be carried out simultaneously throughout the longitudinal dimension of the mounting body and the wear plate or successively in longitudinally localized areas of the mounting body and the wear plate in longitudinal succession in a given longitudinal direction. What is more, it can be carried out entirely in the shop or partly in the shop and partly on a site on which the rail is used.
Accordingly, in accordance with one embodiment of the method of the invention, the mounting body is fixed to the support in a particular position of use, on a site where the rail is used, between steps a) and b), and steps b), c) and d) are carried out on site with the mounting body fixed to the support in said particular position.
When a string of rails is made by this embodiment of the method according to the invention, each joint between the wear plates corresponding to two longitudinally adjoining rails can be made to coincide with the joint between the corresponding mounting bodies, but it is preferable to use the wear plates to insure mechanical continuity between the rails and the mounting bodies to ensure alignment of the wear plates. To this end, one particular embodiment of the method according to the invention is characterized in that several lengths of said mounting body are fixed to said support in said particular position on said site, between steps a) and b), by placing said lengths in alignment with each other in a longitudinal direction, and wherein steps b), c) and d) are carried out with said lengths fixed to said support in said particular position on said site using several lengths of said wear plate, aligned with each other in a longitudinal direction with the joints between them offset longitudinally relative to the joints between said lengths of said mounting body.
Given that the method of the invention implies prefabricating a mounting body and a wear plate with respective specific conformations, the present invention also includes a mounting body and a wear plate as respectively obtained by implementing step a).
In this regard, in an electrically conductive longitudinal body in accordance with the invention, having a substantially constant cross section and a median longitudinal plane of symmetry and including in mutually opposite positions in a transverse direction in said plane, a rigid longitudinal base for mounting it on said support and a longitudinal head for receiving a wear plate, which head has a rebate in the direction away from said plane, on respective opposite sites thereof, and is divided in said plane into two halves joined together by said base and delimiting between them a longitudinal slot open in the direction away from said base in said transverse direction, each of said two halves having opposite said base in said transverse direction a free edge including a plane edge face and a respective rebate and being adapted to flex elastically relative to said base, in particular in the direction toward each other, from a rest configuration in which said mounting body is prefabricated and as far as a maximum elastic flexing configuration, as proposed in FR-A-2 227 148, said two edge faces have an orientation relative to said plane such that they diverge from said base in the direction toward said plane in said rest configuration, and, in a particular intermediate elastic flexing configuration, in which said slot is still open in the direction away from said base in said transverse direction, they are mutually coplanar and perpendicular to said plane and together form a plane face delimiting said head in the direction away from said base in said transverse direction between said rebates.
The body can be made by assembling separate components but is preferably made in one piece from a material chosen from the group comprising aluminum and aluminum alloys.
Apart from the advantages of saving weight, good electrical conduction and good thermal conduction that they already offer in prior art rails of the type indicated in the preamble, compared to all-steel rails, aluminum and aluminum alloys offer advantages specific to the use of the present invention by offering increased possibilities in terms of the choice of the shape and the dimensions of the cross section of the mounting body, for the best possible combination of the elastic flexibility required by the present invention with a satisfactory contact pressure between the two halves of the head of the mounting body and the wear plate, in terms of mutual mechanical connection and electrical conduction between them, and the choice of the composition of the alloy, with the same aim, for a given shape and given dimensions of the cross section of the mounting body, i.e. retaining the same die for extruding the mounting body.
The body can also have various optional features intended to facilitate steps b), c) and d) of the method or to improve the result thereof.
Accordingly, in one preferred embodiment, each half of said head includes, in the direction away from said base in said transverse direction, a rigid edge part comprising in particular the respective edge face and the respective rebate, and, between said rigid edge part and said base, an intermediate part for connecting said edge part to said base, said intermediate part defining in comparison with said base and said edge part a weakened area encouraging elastic flexing of the respective half of said head between said rest configuration and said maximum elastic flexing configuration.
It is therefore certain that, in said predetermined intermediate configuration, the head has a perfectly defined external geometry, closely complementary to the inside geometry of the wear plate, which obtains the strongest possible and most uniform possible mutual application, combined with the facility to choose the elasticity of each half of the head in flexing, which conditions the pressure that each half of the head applies to the respective associated rim of the wear plate in said particular intermediate elastically flexed configuration, i.e. after fabrication of the rail, in particular by the method of the invention.
To this end, also, each rebate is preferably farther from said base in said transverse direction than the connection between the respective rigid edge part and the respective elastically flexible intermediate part.
To increase in particular the cross section of the mounting body, despite the provision of weakened areas of preferred elastic flexing, which are necessarily thin, i.e. in order to respond to the requirements for carrying current, each rigid edge part has an extension toward said base in said direction, alongside the respective elastically flexible intermediate part in the direction away from said plane and forming with it a respective longitudinal slot open toward said base in said transverse direction, in particular so as not to impede flexing of the halves of the head.
The extension of each rigid edge part is preferably conformed to enable an insulative cap of traditional shape to be attached to said base.
What is more if, as is preferred to facilitate steps b) and c) of the method, each half of said head has, in the direction away from said plane, closer to said base than the respective rebate, a respective flat approximately parallel to said plane for applying a respective thrust toward the latter to move said half from said rest configuration to said maximum elastic flexing configuration, said flat is advantageously on the respective extension and closer to said base in said direction than the connection between the respective rigid edge part and the respective elastically flexible intermediate part.
The aforementioned flat advantageously projects in the direction away from said plane relative to the respective adjoining areas of said body, which prevents the risk of the means employed to apply said thrust interfering with those areas.
It is naturally important for the thrust applied to the two halves of the head in the direction toward each other in steps b) and c) does not cause plastic deformation of the halves of the head and to this end each half of said head preferably has, in the area of said slot farthest from said base in said transverse direction, an area of abutment against the other half of said head in said maximum elastic flexing configuration.
To offer a distributed support to the attachment faces of the rims of the wear plate and to reflect the elastic flexing of the halves of the head back toward the rest configuration, in practice only as far as the particular intermediate configuration, during step d) of the method, by firm application of the electrically conductive face of the central strip of the wear plate to the electrically conductive face of the head, each rebate is advantageously formed by a flat facing in the direction away from said plane and progressively converging with it in the direction toward the base in said transverse direction, at least in said particular intermediate configuration. The two rebates thereby apply to the rims of the wear plate a sort of cam effect, the consequence of which is that, as the head is widened by the elastic flexing of its two halves in the direction away from each other perpendicular to the median plane, and symmetrically relative to that plane because of their symmetry, the rebates apply to the rims of the wear plate traction toward the base in said transverse direction so that the two electrically conductive faces are pressed together as uniformly and as flat as possible to minimize the risk of xe2x80x9cpinholingxe2x80x9d of those faces by the effects of arcs struck between them.
This cam effect is preserved by virtue of the elastic prestressing of the head of the mounting body and the opening of the slot thereof at the end of fabrication of the rail, regardless of dimensional variations of the wear plate and the mounting body as a result of thermal expansion when the rail is in service, with the result that the two electrically conductive faces remain firmly pressed together at all times, as uniformly and as flat as possible, and with optimum conditions of electrical conduction between them.
In step a), the rebates and the rims of the wear plate are preferably dimensioned in said transverse direction so that the part of each rebate farthest from the electrically conductive face of the body in said transverse direction remains disengaged from the respective corresponding rim at the end of step d), so that no obstacle impedes this effect.
What is more, to facilitate fitting the wear plate to the head of the mounting body in step c), each half of the head preferably has, between the respective outside face and the respective rebate, an end facet facing away from said plane, Joining the respective end face and the respective rebate and progressively converging with said plane in the direction away from the base in said transverse direction, in particular in the maximum flexing configuration. In this configuration, these facets constitute a bevel on respective opposite sides of the combination of the end faces of the halves of the head, to guide the rims of the wear plate as the latter is engaged on the head, in the direction toward the base of the body in said transverse direction.
To constitute the wear plate of the rail, in particular when it is made by the method according to the invention, the invention proposes an electrically conductive longitudinal plate having a substantially constant cross section and a median longitudinal plane of symmetry and including a flat central strip straddling said plane, having two mutually opposite faces, and two lateral rims on respective opposite sides of said plane and projecting from the same one of said faces, having a face directed toward said plane that converges therewith in the direction away from said central strip in a transverse direction of said plane to define a hook shape, in which wear plate said faces of its central strip are plane and perpendicular to said plane.
Said plate can obviously be assembled from several components but it is preferably made in one piece from a material chosen from the group comprising stainless steel, copper and copper alloys.
To cooperate with the rebates of the head when they are plane, said faces of the rims, constituting the attachment faces, are preferably plane, enabling them to be applied flat to the rebates in the head in said particular intermediate elastically flexed configuration, i.e. when the wear plate has been assembled to the mounting body, which encourages electrical conduction at this level.
To this end, in a preferred embodiment of step a) of the method according to the invention, the mounting body and the wear plate are prefabricated so that the rebates and the attachment faces are plane and at the same angle to the corresponding half of the electrically conducting face of the body and the electrically conducting face of the central strip, so that at the end of step d) the rebates and the attachment faces are pressed flat together.
In a particularly simple configuration, each rim advantageously has a rectilinear longitudinal free edge delimiting said respective face or attachment face in the direction away from the central strip in said transverse direction and each rim is preferably flat and connected to the central strip by a respective longitudinal bend.
Given that the method according to the invention imparts to the rail obtained, of the type indicated in the preamble, a structure which is novel in itself, the present invention also provides a longitudinal electrical power supply rail of that type, which can be made by the method according to the invention, or by some other method, if necessary, said rail including two electrically conductive longitudinal components fastened together having respective substantially constant cross sections and a common median longitudinal plane of symmetry, namely a mounting body for mounting said rail on a support and a wear plate which is worn by said mobile,
said mounting body including, in mutually opposed positions in a transverse direction in said plane, a rigid longitudinal base for mounting it on said support and a longitudinal head for receiving said wear plate, which head is delimited in the direction away from said base in said transverse direction by an electrically conductive face straddling said plane and having a rebate in the direction away from said plane on respective opposite sides of said electrically conductive face, said head is divided in said plane into two halves joined together by said base and delimiting between them a longitudinal slot open in the direction away from said base in said transverse direction, each of said two halves having opposite said base in said transverse direction a free end including a respective half of said electrically conductive face of said body and a respective rebate, and
said wear plate including a flat central strip for transmitting electrical power to said mobile, straddling said plane, having opposite said base in said transverse direction a contact face for said mobile and facing toward said base in said transverse direction an electrically conductive face bearing flat on said electrically conductive face of said body and two lateral rims on respective opposite sides of said plane and forming a projection toward said base in said transverse direction relative to said central strip, each of said rims having, facing toward said plane, an attachment face for attaching it to said body, which attachment face converges with said plane in the direction away from said central strip in said transverse direction to define a hook shape interengaged with a respective rebate so that said wear plate is fastened to said head of said mounting body by a mutual nesting effect, and said halves of said head are held in a particular configuration prestressed in elastic flexing by said rebates bearing against said attachment faces of said wear plate in the direction away from said plane, as proposed in FR-A-2 227 148, in which rail said electrically conductive face of said mounting body and said electrically conductive face of said wear plate are plane and perpendicular to said plane and said longitudinal slot is open in the direction away from said base in said transverse direction in said particular elastic flexing prestressing configuration in which said halves of said head are retained by bearing engagement of said rebates against said attachment faces of said wear plate in the direction away from said plane.
When the rail is fabricated by the method according to the invention, the particular elastically flexed prestressed configuration is naturally the aforementioned particular intermediate elastically flexed configuration.
The rail can also have all of the features resulting either from the different variants of the method according to the invention or the configuration of the mounting body and the wear plate in accordance with the invention, according to the above embodiments thereof.
In particular, a contact grease is advantageously disposed at least between said electrically conductive faces and preferably between said rebates and said attachment faces, and said rebates and said attachment faces are advantageously plane, converge toward said plane in the direction toward said base in said transverse direction, and are pressed flat together.
As a consequence of fabrication by the method according to the invention, on the one hand, and in a manner that is particularly advantageous in allowing a worn or damaged wear plate to be replaced without it being necessary also to change the body, on the other hand, each half of said head is advantageously adapted to flex elastically relative to said base in the direction toward said plane as far as a maximum elastic flexing configuration in which the maximum dimension of said head perpendicular to said plane between said halves of said electrically conductive face of said body and said rebates is at most equal to the width defined between said rims perpendicularly to said plane in an area of maximum closeness thereto in the direction away from said central strip in said transverse direction.
Accordingly, by returning the head to its maximum elastically flexed configuration, the wear plate can be demounted from it, a new one fitted and the head allowed to return to its rest configuration, in practice until its two halves abut against the rims of the new wear plate, again in the particular intermediate configuration.
This operation can be carried out in the shop, after demounting the rail from its support on its site of use and before remounting the rail on its support, but is preferably carried out on site.
To this end, the present invention proposes a method of renovating a rail when its wear plate is worn out or damaged, in which method said mounting body of said rail, said halves of said head of which can flex elastically relative to its base, is fixed to a support in a particular position of use on a site on which said rail is used, said method being carried out on said site with said mounting body fixed to said support in said particular position and including the following succession of steps:
e) applying to said two halves of said head opposite thrusts to move them toward each other, perpendicular to said plane, from said rest configuration to said maximum elastic flexing configuration,
f) maintaining said thrust to retain said two halves of said head in said maximum elastic flexing configuration, separating said wear plate from said head to separate it from said mounting body,
g) maintaining said thrust to retain said two halves of said head in said maximum elastic flexing configuration, nesting said wear plate over said head to place said electrically conductive face of said wear plate in bearing engagement with said halves of said electrically conductive face of said body and to place said rims on respective opposite sides of said head, facing said rebates, and
h) releasing said thrusts while holding said electrically conductive face of said wear plate in bearing engagement with said halves of said electrically conductive face of said body so that said two halves of said head flex elastically toward each other, perpendicularly to said plane, and said rebates abut in this direction against said attachment faces of said rims of said wear plate, which hold said two halves of said head prestressed in elastic flexing in said particular configuration in which said two halves of said electrically conductive face of said body are also mutually coplanar and said electrically conductive face of said wear plate is therefore pressed flat against it.
In a variant, the following succession of steps can be effected between steps f) and g):
i) releasing said thrusts so that said two halves of said head flex elastically in the direction away from each other perpendicularly to said plane and assume a rest configuration, and
j) applying said thrusts again to said two halves of said head to move them from said rest configuration to said maximum elastic flexing configuration.
To avoid at least partly irreversible plastic deformation of the mounting body on applying the thrust intended to return it to its maximum elastically flexed configuration, each half of the head naturally preferably comprises, in the area of said slot farthest from the base in said transverse direction, an area which abuts against the other half of the head in the maximum elastically flexed configuration.
What is more, to facilitate the application of said thrust, each half of the head preferably has, in the direction away from said plane, nearer the base than the corresponding rim of the wear plate, a respective flat, approximately parallel to said plane, for applying a respective thrust toward the latter in order to move said half into the maximum elastically flexed configuration, each flat advantageously projecting in the direction away from said plane relative to the respective adjoining areas of the rail so that the means used to apply said thrust do not interfere either with the wear plate to be changed or with the new wear plate.
The renewal method according to the invention can be carried out in the shop, after demounting the rail from its support on the site of use and returning it to the shop, which then necessitates returning the rail to its site of use to mount it again on its support, or more usually replacing it immediately with a new or renovated rail, and storing it after renovation for installation on a new site. It is consequently preferable to carry it out on the site on which the rail is used, with the mounting body fixed to its support in its particular position of use, and with the mounting body fixed to the support.
What is more, the renewal method according to the invention can be carried out simultaneously throughout the longitudinal dimension of the rail but, for reasons of the overall size of the equipment used for this purpose when the method is carried out on site, in particular, it is preferable to carry it out successively in longitudinally localized areas of the rail in longitudinal succession in a given longitudinal direction.
The method is therefore advantageously carried out on site on several lengths of rail longitudinally aligned with each other, with the joints between the new lengths of wear plate offset longitudinally relative to the joints between the lengths of mounting body, which enables use of the wear plates to insure mechanical continuity between the successive rails and to align the wear plates optimally, despite possible alignment defects between the mounting bodies, to limit the abrasion suffered by the pick-up member, such as a shoe, on passing from one wear plate to another.
To facilitate steps e), f), g), h) and where applicable steps i) and j) of the renewal method according to the invention, in particular on site, and likewise steps b), c), d) of the fabrication method according to the invention, in particular on site, the present invention proposes a carriage adapted to travel along the rail or the mounting body and carrying out those steps as it moves forward.
To this end, the carriage is characterized in that it includes:
a rigid chassis having a median longitudinal plane of symmetry,
removable mechanical connecting means between said chassis and said mounting body in an orientation in which said median longitudinal plane of symmetry coincides with the median longitudinal plane of symmetry of said mounting body, said means supporting said chassis via said mounting body and guiding longitudinal movement of said chassis in translation relative to it,
lateral thrust means on respective opposite sides of said longitudinal plane and symmetrical to each other with respect to said plane, at a level corresponding to an area of said head of said mounting body not covered by said wear plate when said rail is fabricated,
means for controlled forcible movement of said lateral thrust members toward and away from said plane, perpendicularly to it, retaining their mutual symmetry,
a central thrust member disposed in said plane, and
means for controlled forcible movement of said central thrust member both ways in a transverse direction in said plane.
To facilitate the forward movement of the carriage, said mechanical connecting means are preferably rolling means.
Similarly, to this end, said lateral thrust members advantageously include at least one pair of rollers freely rotatable about a respective axis parallel to said transverse direction in said plane on a respective slider and said means for moving said lateral thrust members include slideways on said carriage for guiding said sliders in a direction perpendicular to said plane with no other possibility of relative movement and adjustable means for positioning said sliders along said slideways. In a particularly simple manner, said means for adjustably positioning said sliders include a screw mounted to rotate on said chassis about an axis perpendicular to said plane, immobilized against any other movement relative to said chassis, and meshing with respective opposite threads of said sliders.
Said lateral thrust members preferably include two sets of said pairs, symmetrical to each other with respect to a particular transverse plane of said carriage, constituting a plane of symmetry for said central thrust member, and said means for moving said lateral thrust members constitute two respective corresponding sets which are mutually independent.
In a particularly simple and effective manner said rolling means are said rollers. In particular, if the mounting body of the rail includes flats projecting relative to the adjoining areas in order to receive the thrust adapted to move it to the maximum elastically flexed configuration, each roller advantageously has an annular groove adapted to bear on a respective flat of said mounting body in areas on respective opposite sides thereof, which means that the carriage is supported by the mounting body in the required position and that the carriage is guided, in this position, along the mounting body or the rail.
Similarly, said central thrust member is preferably a roller freely rotatable about a transverse axis on a slider and said means for moving said central thrust member include a slideway on said carriage for guiding said slider in said transverse direction with no other possibility of relative movement and means for positioning said slider adjustably along said slideway. Said means for adjustably positioning said slider can include a screw mounted on said slider to rotate about a transverse axis of said plane, immobilized against any other movement relative to said slider, and meshing with a thread of said chassis.
Other features and advantages of the various aspects of the present invention will emerge from the following description, which relates to a non-limiting embodiment of the invention, and the accompanying drawings, which constitute an integral part of the description.